textproduct: Albany

WHAT HAS CHANGED

Min temps were trended colder tonight into Thu morning with a blend of the NBM and MAVMOS guidance. Some areas of frost are possible in the southern reaches of Lake George and near Glens Falls where temps may fall into the mid 30s. A Frost Advisory may be needed for southeast Warren County and potentially portions of southern VT if temps trend colder from the upper 30s and scattered frost.

A slight westward shift with the coastal low Fri into the weekend, but the timing of rain and stronger winds remains uncertain which keeps confidence low. Winds/Wind gusts were slightly increased above the NBM guidance late Fri into Sat.

KEY MESSAGES

1) Continued dry conditions with below normal temps continue through Thursday.

2) While forecast confidence is low on the exact track and timing of a potential coastal low Friday into the weekend, there is a low to moderate chance for breezy conditions for locations from the Capital Region south and east.

DISCUSSION

KEY MESSAGE 1... A strong Canadian sfc anticyclone over south-central Quebec continues to funnel dry and chilly air over the forecast area this morning. A weak upper level disturbance continues to allow for some higher clouds to intermittently stream into the region. Some patchy to localized areas of frost continue mainly over the northern zones, as temps continue to fall into the 30s and 40s. Some patchy radiational mist in the sheltered valleys and near major bodies of water will burn off after daybreak. The strong subsidence from the surface high will yield mostly sunny skies. Deeper mixing and a sfc pressure gradient between between the strong high and low pressure near the Mid Atlantic corridor will yield breezy northeast/east winds 10-15 mph with some gusts 20-25 mph with temps running slightly below with upper 50s to lower 60s over the higher terrain and mid and spotty upper 60s in the valleys.

The Rex Block that sets up during the day continues into tonight with a closed H500 anticyclone over southeast Ontario the Upper Great Lakes Region north of a closed low over the Ohio Valley and a mid-level trough over the TN Valley and Mid Atlantic Region. The strong sfc high remains over south/southeast Quebec yielding near ideal radiational cooling conditions again with lows falling into the 30s and lower/mid 40s. The growing season has ended over the south/southwest Adirondacks where areas to locally widespread frost may occur. Temps falling into the mid to upper 30s with scattered to locally areas of frost over southern VT and portions of the Lake George northern Saratoga Region. Some scattered frost is also possible in the Mohawk/Schoharie Valley and eastern Catskills. The one zone we may need a Frost Advisory for is southeast Warren County later. Most other zones are borderline. The lower to mid 40s are expected from the Capital District/mid Hudson Valley south and east. The NBM was blended with the MAVMOS for lows. Also, some localized patchy radiational mist is possible in the major river valleys and sheltered valleys. The low temps are about 10-15 degrees below normal. Temps rebound nicely on Thu trending closer to seasonal normals and it will be breezy as the coastal low forms well off the Mid Atlantic Coast near the Gulf Stream of the western Atlantic. Ridging with the Rex Block continues over southeast Canada, the Great Lakes Region and Northeast for the day.

KEY MESSAGE 2...

Thu night into Fri attention shifts to a developing oceanic or coastal low near 35N/70W in the western Atlantic. The evolution and development of the storm looks like it will be east of the Mid Atlantic Region during this time frame, as multiple short- wave disturbances try to phase, but the medium range guidance/ensembles and EC/GFS AI still vary on the timing, evolution and track of the storm. A shift westward closer to the coast has occurred with some of the guidance (some runs of the GFS and CMC guidance), but the track looks slower on some the western most solutions like the latest EC and some of the ensemble members with impacts not until late Sat pm/Sat night. However, the latest GFS is fast moving the wave towards Cape Cod and southeast New England Fri night into Sat, and then retrograding or meandering the storm back to the west/southwest over eastern New England to close the weekend and open next week. This scenario is more of a eastern most solution. The EC would have the intense and deep coastal wave move towards Long Island and southeast New England Sat night and then shift it back to the west/southwest towards coastal NJ and the Delmarva Region. The timing and evolution issues make the impacts for eastern NY and western New England uncertain, but a shift towards the weekend looks likely if the western most scenario or cluster the EC ensemble and AI leans toward. The solution track well offshore impacting southeast New England and Cape Cod is still there. However, the NBM and WPC continue to lean towards the third scenario or cluster where the storm tracks closer to southeast New England and Long Island for periods or occasional bands of showers (light to moderate beginning late Fri pm /Fri night) from the I-87 or Hudson Valley corridor eastward continuing into the weekend before decreasing on Sunday. It will become breezy or brisk as gusty north to northeast winds develop. H850 -u winds anomalies (easterlies) become 2 to 4 STDEVs above normal with a strong low-level jet late Fri into Sat.

The forecast continues to lean towards the NBM with slight to low chances (20 to 40%) of showers especially from the Capital Region south and east Fri pm into Fri night with chances of rain increasing to 40-60% from the Hudson River Valley east across western New England by Sat-Sat night. The 48-hr NBM probs for >1" of rainfall for the 48-hr period ending 8 am Sunday are slightly lower compared to yesterday in the 20-50% range from the Capital District south and east with the highest probs over NW CT compared to yesterday. The chances for impactful rainfall continue to remain low with probabilities for the 48-hr period ending 8 am Monday indicating locations south and east of the Capital Region only in the 20-30% range. NBM probabilistic guidance for the 24-hr period ending 2 am Sun has a 30 to 50% chance > 35 mph gusts for locations mainly south of the Capital District including the eastern Catskills, mid Hudson Valley, portions of the Taconics, Berkshires and Litchfield County. These winds could blow around unsecured outdoors objects or knock down some foliated tree limbs. Slight shifts with the storm track will make a difference over the next couple days, so trends will continue to be monitored. Temps will be near normal through the weekend into early next week. The chances for showers diminish by early next week, as the low finally moves away.

AVIATION /06Z WEDNESDAY THROUGH SUNDAY/

Through 06Z Thu...VFR conditions are expected mainly the next 24 hours for KGFL/KALB/KPOU/KPSF. Some patchy MVFR/IFR radiational mist may impact KGFL prior to 11Z/Wed and we used a TEMPO group between 07Z-11Z/Wed to account for it. We were not confident for radiational mist or low stratus at KPSF and kept it VFR prior to 12Z/Wed. Some shallow radiational mist/ground fog may get near KALB, but with sct-bkn cirrus around we kept it VFR. The surface high over southern central Quebec will keep the skies mostly clear/clear during the day into Wed night with just a few-sct cirrus. The winds will be variable in direction at 4 KT or less to calm prior to day break. The winds will increase from the northeast/east at 8-13 KT in the late morning through most of the afternoon with some gusts around 20 KT with the highest gusts at KPSF and KPOU. The winds decrease to 10 KT or less after 22Z/Wed and become light to calm early tonight.

Outlook...

Thursday Night: No Operational Impact. NO SIG WX. Friday: Low Operational Impact. Breezy. NO SIG WX. Friday Night: Moderate Operational Impact. Breezy. Chance of SHRA. Saturday: Moderate Operational Impact. Breezy. Chance of SHRA. Saturday Night: Moderate Operational Impact. Breezy. Chance of SHRA. Sunday: Moderate Operational Impact. Breezy. Chance of SHRA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.